Means for controlled tilting of a ladle



Feb. 24, 1970 v. H. AMES 3,496,792

MEANS FOR CONTROLLED TILTING OF A LADLE Filed May 1. 1968 2 She ets-Sheet 1 FIG. 2

FIG. I

INVENTOR.

VICTOR H. AMES ATTORNEYS.

Feb; 24, 1970 v. AMES 3,496,792

MEANS FOR CONTROLLED TILTING OF A LADLE Filed May 1, 1968 ZSheets-Sheet 2 ATTOBNEISQM United States Patent O 3,496,792 MEANS FOR CONTROLLED TILTING OF A LADLE Victor H. Ames, Midlothian, Ill., assignor to Whiting Corporation, a corporation of Illinois Filed May 1, 1968, Ser. No. 725,632 Int. Cl. F16h 57/10 US. Cl. 74-411.5 6 Claims ABSTRACT OF THE DISCLOSURE The ladle is supported on trunnions for tilting movement about a pivot axis defined by such trunnions. When the ladle is in an upright position and filled with molten material, its center of gravity is above the pivot axis thereby producing a tendency in the ladle to tip. After the ladle has tilted and thereby discharged a portion of the molten mass, the center of gravity will have shifted such that the ladle is subjected to an uprighting torque. The ladle will be subjected to this uprighting torque as it continues to tilt for discharging the remainder of the molten mass. A manually operated input shaft is connected with one of the trunnions through a gear train. Double acting brake means are connected to this gear train. One of the brakes prevents tipping of the ladle in any position thereof against an over-turning torque, this brake means cooperating with the input shaft for being automatically released in a controlled manner thereby to allow tilting of the ladle. The other brake serves to prevent righting of the ladle when it is being subjected to an uprighting torque, this brake cooperating with the input shaft in a driving mode to cause tilting of the ladle for discharging all of the molten mass therefrom.

Background of the invention As is known to those skilled in the art, ladles are tiltably mounted on trunnions and are associated with a gear train for tilting the ladle to discharge the molten mass therefrom. In many installations, the ladle is tilted manually through a hand wheel mounted on an input shaft associated with the gear train. In order to provide for a manually applied input torque of minimum value, the ladle trunnions are positioned such that the center of gravity of the molten mass will be just above the pivot axis defined by the trunnions thereby making the peak overturning torque as equal as possible to the peak uprighting torque. During a pouring operation, the center of gravity of course changes due to discharge of the molten material. Because .of the initial very close relationship between the pivot axis and the center of gravity, shifting of the latter will result in a torque reversal, i.e., in countertendencies of the ladle to tilt in opposite directions during a pouring operation. That is to say, as the center of gravity is located above the pivot axis when the filled ladle is in an upright condition, there is a tendency of the ladle to tip. However, after the ladle has been tilted to a certain extent and a portion of the molten material discharged, the center of gravity will shift relative to the pivot axis such that the ladle then tends to right itself.

In arrangements wherein ladles are tilted by manually operated hand wheel, the above described condition may be a dangerous one as the center of gravity of the molten mass may shift quite rapidly and cause the ladle to tilt or run away from the operator. One attempt to solve this problem has included the use of a worm gear drive between the injut shaft and the ladle trunnions. A worm gear drive is quite inefiicient and therefore requires a substantial input torque to achieve "ice tilting of the ladle. Efliciency of the worm gear drive can be improved by the use of lubricants, but this is self-defeating as lubrication may very well result in the input shaft being rotated due to tipping or righting of the ladle, the torque so applied to the input shaft being suflicient to overpower the operator. Further, the prior art arrangements may allow run away if the operator through inadvertence fails to maintain proper torque control over the hand wheel. The present invention provides a simple and highly efficient gear drive between the input shaft and the trunnions, this gear drive being uniquely associated with alternately actuated dual brake means.

Objects of the invention A primary object of the present invention is the provision of new and improved means for controlled tilting of a ladle, such means including a gear train associated with first and second brake means which are alternately operable during a pouring operation to counteract the tendency of the ladle to tip and to right itself.

Another object of the invention is the provision of new and improved ladle tilting means of the type described, wherein the brake means coperate with an input shaft such that during a pouring operation one of the brake means is released in a controlled manner and the other brake means operated in a drive mode.

Still another object of the present invention is the provision of new and improved ladle tilting means of the type described, such means including a highly eflicient gear train associated with dual brake means which are alternately operable during a pouring operation.

These and other objects and advantages of the invention will become apparent from the following specification disclosing a preferred embodiment shown in the accompanying drawings.

Description of the drawings FIG. 1 is a side elevational view of a ladle with which the present invention is associated;

FIG. 2 is an enlarged section taken along the line 22 of FIG. 1; and

FIG. 3 is an enlarged section taken=along the line 33 of FIG. 1.

Description of a preferred embodiment Referring to FIG. 1, a ladle bucket 10 includes a pair of diametrically oppositely disposed trunnions, one trunnion being illustrated and designated as 11. The trunnion 11 is received in a bearing sleeve 12 and keyed thereto as by means of a key 14. This bearing sleeve is rotatably mounted in a gear box 15 by means of pairs of annular ball-bearing assemblies 16 and 17. The gear b x is suspended from the distal end of one of the legs of an inverted, U-shaped frame 18, the latter being suitably supported, as by means of an overhead crane (not shown). It will be understood that the other leg of the U-shaped frame 18 is journaled with the other trunnion on the ladle in any suitable manner thereby to mount the bucket 10 for pivoting movement about an axis defined by the trunnions 11.

A gear 20 is mounted on the bearing sleeve 12 and connected for movement therewith by a key 21. The gear 20 is provided with peripherally disposed teeth 20a in meshing engagement with the teeth of a pinion gear 22 which may be integral with a shaft 24, opposite ends of the latter being journaled in the gear box 15 by annular sets of ballbearing assemblies 25, 26. A gear 28 is mounted on the shaft 24 for rotation therewith by means of a key 29.

The gear 28 has peripherally disposed teeth 28a in meshing engagement with teeth on a gear 30 (FIG. 3). The gear 30, which is in the nature of a thrust gear, is

internally threaded and in threading engagement with threads 31 on an input shaft 32. This input shaft has one end thereof disposed externally of the gear box and supporting a hand wheel 33, the latter being fixed to the input shaft by a key 34. The input shaft has an enlarged portion 35 journaled in annular ball-bearing assembly 36, the latter being suitably mounted in a cavity formed in the wall or plate 15a of the gear box. The inner end of the input shaft is externally threaded and mounts a suitable fastener 37. This end of the shaft 32 is received within the central bore of a brake plate 38 and connected thereto by means of a key 39. The brake plate includes an integral hub portion 38a journaled in a ball-bearing assembly 40 which is suitably mounted in a bore provided in a partition wall portion 15b.

Another brake plate 42, similar to the clutch plate 38, is mounted on the shaft 32 adjacent the enlarged portion 35 thereof and keyed to the input shaft by means of a key 43. The brake plate 42 has an annular brake or friction surface 42a for gripping engagement with one face of a ratchet disk 44, the latter being freely rotatably mounted on a hub portion 42b of the brake plate 42. The disk 44 includes a concentric groove receiving a thrust bearing assembly 45 which is adapted for rolling engagement with one face of a ring 46. Upon the application of predetermined axial pressure between the disk 44 and the plate 42, the thrust bearing 45 will establish a gripping engagement between these two members. It will be understood the ring 46 is Secured to the gear 30 for rotation therewith.

The brake plate 38 includes an annular friction or brake surface 38b adapted for gripping engagement with one face of a disk 48, the latter being freely rotatably mounted on the hub portion 380 of the brake plate 38. The disk 48 includes a concentric groove receiving a thrust bearing assembly 49, the latter being adapted for gripping engagement with one face of a ring this ring is secured to the gear 30 for rotation therewith. It will be understood the thrust bearing assembly 49 is the same as the assembly 45 as it permits free rotation between the mating faces of the ring 50 and disk 48, but establishes a gripping engagement between such mating surfaces upon the application of an axial force of predetermined magnitude.

An annular member 52 in the nature of a pawl has the teeth 52a thereof in meshing engagement with the teeth 44a on the disk 44. The pawl 52 is mounted on a stub shaft 53 by suitable means (not shown) such that the pawl 52 is permitted to rotate in one direction only. A similar pawl 55 has the teeth 55a thereof in meshing engagement with the teeth 48a on the disk 48. The pawl 55 is mounted on the stub shaft 53 by suitable means (not shown) for rotation in one direction only, the direction of movement of the gear 55 being opposite the direction of movement of the gear 52. The means for mounting the pawls 52, 55 may take a variety of forms of known construction, and may, for example, be in the nature of ratchets. One end of the stub shaft 53 is mounted in a bore 56 formed in the partition wall portion 15b. The other end of the stub shaft is mounted in a bore 57 formed in the wall or shell of the gear box 15. This shaft is suitably keyed against rotation.

The operation of the ladle tilting mechanism acc rding to the present invention is as follows:

When the ladle 10 is in the upright position illustrated and contains a full charge or load of molten material, the center of gravity is disposed above the ladle pivot axis substantially in a vertical plane containing the latter. Accordingly, there is a tendency of the ladle 10 to tilt in one direction or the other. Assume that the ladle 10 attempts to tilt in the pouring direction, i.e., clockwise with respect to FIG. 1. The tendency of the ladle to tilt in this direction will result in rotation of the gear 30 relative to the threads 31 such that the gear 30 will move to the right as viewed in FIG. 3. This movement of the gear 30 will force the ring 50 against the thrust bearing 49 until the pressure is such that the brake plate 38 will grip or frictionally lock-up with the disk 48 thereby attempting to rotate the latter in the same direction as the gear 30. However, the pawl 55 will prevent rotation of the disk 48 in this direction. The shaft 32 is keyed to the plate 38 which is now locked against rotation in the direction indicated, The gear 30 in essence becomes locked to the shaft as the former can no longer rotate relative to the latter. Accordingly, the brake defined by members 38, 48, 50 and 55 will have come into play to prevent tipping of the ladle 10 in the direction just mentioned.

Now, when the operator wants to tilt the ladle bucket 10 in a clockwise direction for discharging the contents thereof, the operator will exert a force on the hand wheel 33 for turning the same in a clockwise direction. The gear 30 will not be allowed to rotate because of the lock-up just described. Accordingly, the relative rotation between the input shaft 32 and the gear 30 will cause backing off or movement of the latter to the left thereby decreasing the axial force or pressure between opposite faces of the disk 48 and the adjoining faces of the ring 50 and brake plate 38 to allow the latter to slip relative to the disk 48. This will result in rotation of the gear 30 and in turn tipping of the bucket 10 to commence pouring.

In the situation just described, it will be appreciated there can be no relative movement bet-ween the gear 30 and the shaft 32 without movement of the brake plate 38, as the latter is keyed to the shaft 32. The brake plate 38 has an annular friction surface 38b which engages a complementary surface on the adjacent side of the disk 48 thereby to define What may be characterized as a first annular friction formation. The engagement between the annular thrust bearing 49 and an annular surface of the ring 50 defines what may be characterized as a second annular friction formation. It will be readily appreciated that the effective friction radius of the first annular friction formation is greater than the effective friction radius of the second annular friction formation. (This would be true even if the entire face of the brake plate 38 were to be used rather than the peripheral annular surface 38b.) This dilference in effective friction radii gives the operator a mechanical advantage in controllably releasing the brake defined in part by the brake plate 38, the latter being keyed to the shaft 32 as just mentioned. This feature minimizes the possibility of the brake being locked-up to such a degree that the operator would not be able to release the same by manual rotation of the shaft 32 As soon as the gear 30 has rotated but a small amount, the same will again become locked-up with the disk 48 as aforesaid. The operator will now move the hand wheel 33 through another increment of rotation in a clockwise direction to repeat the cycle of operation just described. In other words, the operator in effect actuates the hand wheel 33 to release the brake (defined by the members 38, 48, 50 and 55) in a stepped or intermittent manner to allow tipping of the ladle under controlled conditions.

After the ladle has been tilted through approximately 30 in the embodiment shownherein for purposes of illustration, the center of gravity will shift such that the ladle now tends to right itself. This will tend to rotate the gear 30 such that the same will move to the left urging the ring 46 into engagement with the disk 44 and also urging the latter into gripping engagement with the brake plate 42. This squeezing action onthe disk 44 by the ring 46 and the brake plate 42 will tend to rotate the disk 44; however, the disk 44 will not be allowed to rotate in this direction by reason of the ratchet or one-way action of the pawl 52. Accordingly, a lock-up will be defined through the members 42, 44, 46 and 52 to prevent righting of the ladle 10.

The operator now rotates the hand wheel 33 in a clockwise direction and the disk 44 is rotated in the same direction. The pawl 52 will permit movement of the disk in this direction and therefore there is a driving connection established between the input shaft 32, key 43, brake plate 42, disk 44, ring 46 and gear 30 to rotate the ladle in a clockwise direction for discharging the contents thereof.

It will be appreciated that in accordance with the embodiment just described, one of the so-called one-way brakes comes into play during the beginning of a pouring cycle to prevent tipping of the ladle. During this initial movement of the ladle, the hand wheel 33 is actually actuated for controlled releasing of this brake to permit tilting. When the ladle has tilted to a degree wherein a portion of the contents thereof is discharged and the center of gravity shifts such that the ladle tends to right itself, the other brake comes into operation to prevent righting of the ladle. Then, continued clockwise rotation of the hand wheel establishes or sets up a driving mode in the other brake to bring about continued rotation or tilting of the ladle bucket for complete discharge of the contents thereof.

It will be understood that during return of the ladle to the upright position, the center of gravity thereof is below the pivot axis; accordingly, there will be no torque reversal applied to the gear train from the ladle and therefore only the brake constituted by the clutch gear 52 will be used. counterclockwise rotation of the hand wheel 33 will result in intermitten release of this brake to allow righting of the ladle.

The brake plate 42 has an annular surface 42a arranged for frictional engagement with a complementary surface on the disk 44 thereby to define a first annular friction formation. The thrust bearing 45 engages an annular surface on the ring 46 thereby to define a second annular friction formation. The effective friction radius of the first annular friction formation just defined is greater than the efiective friction radius of the second annular friction formation as just defined. This difference in effective friction radii again gives the operator a mechanical advantage for controlled or intermitten release of the brake defined in part by the brake plate 42, the latter being keyed to the input shaft 32. This feature minimizes the possibility of this brake being locked-up to such a degree that the operator would not be able to release the same by manual rotation of the shaft 32.

It will be appreciated that during pouring and also during return of the empty ladle to the upright position, the operator may release the hand wheel at any time which will immediately result in the ladle 10 being braked or locked in the position it then occupies. The ladle can never run away or overpower the operator. This present invention makes manual tilting of the ladle quite safe and easy and will also permit powered operation of the input shaft by a motor of relatively modest torque requirements.

The present invention may be characterized as consisting of two brake disks which are alternately engaged in an automatic manner in response to overturning and uprighting torques to which the ladle is subjected by reason of a shift in center of gravity due to discharge of the molten mass. When a manual input torque is applied which is in opposition to the uprighting or overturning torque, as the case may be, the brake which is in operation ratchets to establish a driving mode thereby to cause tilting of the ladle. When the manually applied input torque is the same as the uprighting or overturning torque, the brake in operation is released or slipped intermittently to allow tilting in the desired direction. According to the present invention the hand wheel can always rotate the ladle, but the ladle can never rotate the hand wheel.

It will be understood that if the ladle is tilted in an opposite direction from the FIG. 1 position, i.e., in a counterclockwise direction, the operation of the dual brake is the same. The only difference is that the pawl 52 would act during the first 30 of ladle rotation and the pawl 55 would act thereafter.

I claim:

1. In a ladle of the type which is mounted on trunnions defining a pivot axis, wherein the center of gravity of the molten mass in the ladle shifts relative to said axis during a pouring operation such that initially there is a tendency of the ladle to tip and that after the ladle has been tilted a predetermined amount for discharging a portion of the molten mass there is a countertendency of the ladle to right itself, means for controlled tilting of said ladle comprising:

(a) an input shaft;

(b) a gear train connecting said shaft with one of the trunnions on said ladle, which gear train includes a thrust gear threadingly engaged with said shaft;

(c) a pair of one-way brakes arranged in opposite functional relationship with each other, each of said brakes including:

(1) a disk and means associated therewith permitting its rotation in one direction only;

(2) a brake plate mounted on said shaft for rotation therewith;

(3) said brake plate having a surface arranged for engagement with a complementary surface on said disk thereby to define a first annular friction formation;

(4) a ring carried by said thrust gear for rotation therewith;

(5) said ring having a surface arranged for engagement with a complementary surface on said disk thereby to define a second annular friction formation;

(6) the effective friction radius of said first formation being greater than the effective friction radius of said second formation; and

(d) said brakes being alternately actuated into their braking modes in response to opposite rotational movements of said thrust gear relative to said shaft, respectively, whereby one of said brakes serves to prevent tilting of the ladle during its initial movement through said predetermined amount and is adapted to be controllably released to allow tilting of the ladle through said predetermined amount, the other of said brakes serving to prevent righting of the ladle after it has been tilted beyond said predetermined amount and being adapted to be operated in a driving mode to cause tilting of the ladle beyond said predetermined amount.

2. The construction according to claim 1 further defined by: each of said disks having a peripheral formation of teeth, each of said means associated with each disk being defined by a pawl member having teeth arranged for meshing engagement with the teeth on the associated disk.

3. The construction according to claim 1 wherein said input shaft mounts a hand wheel for manually rotating the former.

4. In a ladle of the type which is mounted on trunnions defining a pivot axis, wherein the center of gravity of the molten mass in the ladle shifts relative to said axis during a pouring operation such that initially there is a tendency of the ladle to rotate in one direction and that after the ladle has been tilted through a predetermined amount for discharging a portion of the molten mass there is a countertendency of the ladle to rotate in the other direction, means for controlled tilting of said ladle comprising:

(a) an input shaft;

(b) a gear train connecting said shaft with at least one of the trunnions on said ladle;

(c) said gear train including a thrust gear threadingly mounted on said input shaft;

(d) first and second one-way brakes adapted to be alternately actuated by respective opposite rotational movements of said thrust gear so as to lock the latter against further rotational movements as the result of torque forces applied thereto from said ladle;

(e) said first and second one-way brakes being respectively defined in part by a pair of friction rings carried by said thrust gear at respective opposite ends thereof for movement therewith;

(f) said first and second one-way brakes also being respectively defined in part by a pair of brake plates carried by said input shaft for movement therewith; and

(g) said friction ring and said brake plate of each of said brakes having respective annular friction surfaces, the effective friction radius of the friction surface on each brake plate being greater than the effective friction radius of the friction surface on each ring.

5. The construction according to claim 4 further defined by:

(a) each of said one-way brakes including a disk mounted between the associated friction ring and brake plate, which disk includes annular friction surfaces cooperating with respective friction surfaces on such friction ring and such brake plate; and

(b) means associated with one of said disks forpermitting rotation of the latter in one direction only and other means associated with the other of said disks for permitting rotation of the latter only in a direction opposite said one direction. 1 r

6. The construction according to claim 5 wherein said means and said other means associated with respective disks are defined by ratchet and pawl type members.

References Cited UNITED STATES PATENTS 1,309,964 7/1919 Schneider 188134 1,833,224 11/1931 Mullan et al 188-134 2,727,604 12/ 1955 Robertson 192 7 3,219,154 11/1965 Schenck et a1 188134 LEONARD H. GERIN, Primary Examiner US. Cl. X.R. 

